Using the latest data obtained with the NASA Kepler space telescope, astronomers have counted tens of billions of terrestrial planets in our galaxy alone, the Milky Way. They are not only similar to the Earth in size, but also located in the so-called habitat zone. Located at a comfortable distance from their star, which provides a livable environment. And most importantly - the possibility of the existence of water in liquid form
Such an abundance of potentially habitable worlds dramatically increases the likelihood of its existence. Up to reasonable and highly developed. However, studies recently conducted by scientists from an international group, alas, reduce this probability. At least they testify that extraterrestrial life can be very exotic and quite unlike ours.
Oxygen, iron, magnesium and silicon prevail in the composition of the terrestrial planets. Most of these elements are in the form of silicates or metals.
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So to take it according to reason, if they are found somewhere, they will not necessarily have at least a remote resemblance to us. Or the "sister of the Earth" will turn out to be so unnatural that it will not be able to support life at all, despite the seemingly favorable external conditions.
Different ecology
Garik Israelian from the Institute of Astrophysics in the Canary Islands and his colleagues from the Institute of Planetary Sciences (USA) and the University of Porto (Portugal) found that the chemical composition of Earth-like planets can be very different. Which, in turn, affects the existence and formation of biospheres and life there.
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In other stellar systems, planets are found that are similar in composition to the Earth. But far from identical. The 55 Cnc planetary system has a C / O ratio greater than 1 (C / O = 1.12). It contains carbon-rich terrestrial planets
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According to the researchers, the mineral composition of the planets depends on the proportion of carbon and oxygen (C / O), magnesium and silicon (Mg / Si) in the substance from which the planets were formed - in the so-called photoplanetary cloud. And since, as it turned out, the C / O and Mg / Si coefficients can vary over a very wide range - be either more or less than one, then one or the other elements predominate in the composition of the planets. What affects tectonic and volcanic processes, the composition of the atmosphere. And, ultimately, local life, which can take on the most incredible forms.
For example, finding a planet that is close in composition to ours is not so easy. Moreover, he himself - the current chemical composition - could have been completely different if the giant Jupiter had not appeared in the solar system. And then, who knows what kind of monsters would inhabit the Earth? And what kind would we have?
“The construction of planets in a chemical environment that is not typical for the solar system is very common in the Universe,” says Garik Israelian. “And this could lead to the formation of strange worlds, very different from Earth.
- The observed variations in the key C / O and Mg / Si ratios of known stars containing planets implies a high probability of the existence of terrestrial planets outside the solar system - from "relatively terrestrial" planets to planets with a predominance of carbon in graphite and carbide phases, for example, silicon carbide, titanium carbide, echoes another member of the research team, Elise Delgado Mena.
A striking example of almost scientific foresight, by the way, is given by science fiction. In the movie "Avatar" on the beautiful planet Pandora - the satellite of the gas giant - blue aborigines, flying lizards and various six-legged creatures live comfortably. But this world is poisonous to people. And why? Because in the local system there was a "variation in the key C / O and Mg / Si ratios." And life arose that was different from the earthly one.